EP Patent 1,844,222 describes a dual-supercharged combustion engine and a dual supercharging control method. The engine described in this document comprises an additional controllable valve between the turbocharger and the mechanical compressor, which makes the system more complex to achieve and to control (the number of actuators to be controlled is larger). In addition, the control method described in this document does not take account of the physical behavior of the gas flows at the intake.
To overcome these problems, the invention relates, on the one hand, to a combustion engine equipped with a dual supercharging system in which a mechanical compressor is driven by an electric motor and, on the other hand, controlling a combustion engine, wherein the electric motor is controlled by determining a rotational speed setpoint for the positive-displacement compressor using a supercharged volume filling model. Using an electric motor allows reducing of the supercharging energy cost and to achieve faster transient responses at low rotational speeds. The model allows accounting for the physical behavior of the gas flows at the intake. Furthermore, the rotation setpoint of the positive-displacement compressor allows controlling supercharging in a fast, robust and energetically optimal manner.